Sam Burnett, from MediaWatch UK, is speaking as Childline says the number of counselling sessions for children worried about online sexual abuse rose by 24 per cent last year, to 3,716.
Most of these were aged 12-15 and almost two-thirds were girls.
One in eight of the sessions - 459 - related specifically to grooming, an increase of 21 per cent.
Sam Burnett told Premier: "This is a team effort, people everywhere, whether it's looking after their children or whether it's in churches and youth groups, we need to be creating supportive atmospheres where young people do feel able to talk about these issues.
"We need to be open so children do feel that they can share these problems that they're going through, rather than keeping them bottled up or feeling like they have to go through them alone."
"My hope is that we create an environment where young people feel supported and they're not ashamed about things that are going on on the internet, but they feel they can share."
Listen to Premier's Hannah Tooley speak to Sam Burnett here:
